High quality antimicrobial paint composition

ABSTRACT

A high quality paint formulation comprises water, latex polymer, pigment, and a quaternary ammonium compound. The high quality paint is capable of killing gram positive bacteria, gram negative bacteria at a rate of greater than 3 logs within 2 hours of application of bacteria to a painted surface. The high quality paint is also capable of inactivating viruses.

This application is a continuation of currently U.S. application Ser.No. 14/823,123, filed on Aug. 11, 2015, which is a continuationapplication of U.S. patent application Ser. No. 13/552,966, filed Jul.19, 2012, now U.S. Pat. No. 9,131,683, the entirety of which is herebyincorporated by reference, which in turn claims the benefit of U.S.Provisional Patent Application No. 61/541,168, filed Sep. 30, 2011, theentirety of which is hereby incorporated by reference.

This invention was made with Government support under Contract NumberW911NF09C0025 awarded by the U.S. Army Research Office. The Governmenthas certain rights in this invention.

FIELD OF THE INVENTION

This invention relates to a high quality latex paint which contains anantimicrobial agent, in particular a quaternary ammonium compound.

BACKGROUND

Paints typically contain four essential ingredients: carrier liquid,binder, pigment, and additives. Each of such ingredients may comprise asingle component or several different items mixed into the paint.

The carrier liquid is a fluid component of the paint which serves tocarry all of the other paint components. The carrier liquid is part ofthe wet paint and usually evaporates as the paint forms a film and drieson a surface. In latex paints, the carrier liquid is usually water. Inoil-based paints, the carrier liquid is usually an organic solvent. Theamount and type of liquid is usually determined by features of the otherpaint components.

The binder component of a paint is what causes the paint to form a filmon and adhere to a surface. In a latex paint, the binder comprises alatex resin, usually selected from acrylics, vinyl acrylics, or styreneacrylics. In a latex paint, the latex resin particles usually are in adispersion with water as the carrier liquid.

Pigments provide the paint with both decorative and protective features.Pigments are solid particles used to provide the paint with variousqualities, including but not limited to color, opacity, and durability.The paint may also contain other solid particles such as polyurethanebeads or other solids. Pigments and other solids add bulk to the paintand their levels are related to the gloss or flatness of the paint.

A multitude of additives may be included in paints. The additives aretypically used at relatively low levels in the paint formulation, butcontribute to various properties of paints, including rheology,stability, paint performance, and application quality.

Biocides, or specifically, antibacterial agents, are additives whichhave bacteriostatic and bactericidal properties. Biocides work to killbacteria by one or more of several different mechanisms, including butnot limited to interfering with cell wall synthesis, damaging the cellmembranes, inhibiting protein synthesis, and interfering with nucleicacid synthesis. Some biocides may also have anti-viral effects, servingto inactivate viruses, such as cold and flu viruses.

A variety of biocidal agents are well known and are used for variouspurposes. Such biocides include inorganic biocidal agents, for example,those containing metal ions, such as silver, zinc, and copper. Otherinorganic biocides include phosphates, metal ion, metal or other biocidecontaining zeolites or hydroxyapatites. There are also organic biocidesincluding organic acids, phenols, alcohols, and quaternary ammoniumcompounds.

Quaternary ammonium compounds act as biocides by damaging cell membranesand killing bacteria. This mechanism is likely due to the positivecharge on the quaternary ammonium compounds which interact with thenegative charge sites of the bacteria.

Quaternary ammonium compounds are not typically added to latex paints,due to a negative effect on the quality of the paint. The prior art hasrecognized that when added to latex paints, quaternary ammoniumcompounds cause an undesirable increase in viscosity and cause thepolymer and pigments to precipitate. Without being limited to anyparticular theory, it is believed that the cationic nature of thequaternary ammonium compounds is not compatible with the generallyanionic nature of latex paint formulations which results in theprecipitation of the components from the dispersion. The precipitationcauses the paint to have an undesirable appearance as the precipitateparticles cause the dry paint film to have a grainy appearance ortexture.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises, in one embodiment, a paint compositioncomprising water, latex binder resin, pigment, and additives, whereinsuch additives include, but are not limited to, a quaternary ammoniumcompound. In one useful embodiment, the latex binder resin and thequaternary ammonium compound have a compatibility score of less than 0.7g, for example, less than 0.5 g, and further for example, less than 0.35g, as measured by the Polymer/Quaternary Ammonium Compound CompatibilityTest (hereinafter “Compatibility Test”) described herein. In anotherembodiment, the invention comprises a high quality paint compositionhaving broad spectrum biocidal capabilities. In one useful embodiment,the dried paint film is capable of reducing gram positive bacteria, gramnegative bacteria, and viruses by greater than 3 logs within 2 hours ofapplication of the bacteria or viruses to the coated surface. Bacterialand viral reduction is measured in a test based on the JapaneseIndustrial Standard (JIS) Z 2801 as described herein and compared to acontrol paint that does not contain a quaternary ammonium compound.

In a particularly useful embodiment, the paint composition of thepresent invention has one or more of the following characteristics:pigment volume concentration (PVC) of less than 60, about 25% to about65% by weight solids, at least 17% by weight binder up to about 55% byweight binder polymer solids, and at least 10% by weight of a hidingpigment, for example, titanium dioxide. In one useful embodiment of theinvention, the pigments used in the paint composition have a minimumfineness of grind by Hegman gauge of at least 4, for example, at least5. Further, the paint composition may have one or more of the followingqualities: good application and appearance, good stability, and gooddurability. Good application and appearance refers to one or more of thefollowing properties: flow and leveling, color uniformity, durability oftinted coating to shear, contrast ratio, tint strength, and appliedhide. Good durability refers to one or more of the following properties:abrasive scrub resistance as measured by ASTM Test Method D 2486-74A(>400 scrubs), block resistance measured by ASTM-D 4946-89, (>6 after 1day and 7 days), and adhesion measured by ASTM-D3359 Test Method A(greater than 3 A). In another useful embodiment, the paint composition,when applied to a surface and dried, has a Gloss at 60° of 5-85 units,for example, over 5 up to 85 units.

The term “quaternary ammonium compounds” as used herein refers toquaternary ammonium salt antibacterial agents having the structuralformula:

wherein R₁ and R₂ are linear or branched chain alkyl groups or mixturesof groups having 1-7 carbons, R₃ is a linear or branched chain alkylgroup or mixtures of groups containing 6-20 carbons, and R₄ is selectedfrom linear or branched chain alkyl groups or mixture of groups having6-20 carbons, benzyl or C1-C18 alkyl benzyl groups, or

where R₃ and R₄ may be the same or different from each other, and Xrepresents a halide, in particular chloride, bromide or iodide,carbonate, methosulfate, or saccharinate. In a particularly usefulembodiment the quaternary ammonium compound does not contain or issubstantially free of silicon species. Useful examples of quaternaryammonium compounds include, but are not limited to n-alkyl (C8-C18)dimethyl benzyl ammonium chlorides, benzalkonium chloride (where thealkyl side chain is C8, C10, C12, C14, C16 or C18 or mixtures thereof),n-alkyl (C8-C18) dimethyl ethylbenzyl ammonium chlorides, dialkyldimethyl ammonium chlorides (where the alkyl side chain is C6-C12),n-alkyl dimethyl benzyl ammonium chloride, and didecyl dimethyl ammoniumchloride, octyl decyl dimethyl ammonium chloride, dioctyl dimethylammonium chloride, didecyl dimethyl ammonium chloride, and mixtures ofsame. A variety of useful quaternary ammonium compounds are commerciallyavailable including, but not limited to Barquat®MB-50, Barquat®MB-80,and Bardac® 2250 quaternary ammonium compounds available from Lonza,Inc., BTC®1010, BTC®2125, and BTC®818-80% available from Stepan Company.Other useful quaternary ammonium compounds may include compounds havingthe following structures:

where R₁ is C₈-C₁₈-alkyl or -alkenyl, for example, -alkyl, where R₂ isC₈-C₁₈-alkyl or -alkenyl, for example, -alkyl, aryl or C₇-C₁₈-aralkyl,in which the aromatic rings can additionally be substituted, for exampleby chlorine and/or bromine, where R₃ is C₁-C₄-alkyl, for example,methyl, and can be identical or different, where R₄ is H or methyl, andwhere A is an anion of an organic or inorganic acid. Possible anions Aare, for example, chloride, bromide, acetate, propionate, benzoate or 1equivalent of sulfate. The radicals R₁ and R₂ in Formula II can beidentical or different. For example, in one useful embodiment, compoundsof Formula II in which R₁ and R₂ are C₁₀-C₁₂-alkyl or both radicals R₁and R₂ are C₁₀-C₁₂-alkyl may be used. Compounds of the Formulas II andIII are, for example, octyl-trimethylammonium bromide,decyl-trimethyl-ammonium chloride, didecyl-dimethylammonium chloride,dedecyl-methylhydroxyethylammonium propionate, lauryl-trimethylammoniumchloride, lauryl-pyridinium chloride, hexadecyl-trimethylammoniumchloride, stearyl-trimethylammonium chloride andstearyl-dimethylbenzylammonium chloride. Paint compositions inaccordance with the present invention may contain a single quaternaryammonium compound, as described above, or mixtures of two or morequaternary ammonium compounds.

A paint composition made in accordance with the present invention maycomprise about 0.25% by weight up to about 3% by weight, for example,about 0.5% to about 1.5% of at least one quaternary ammonium compound.

Paint compositions in accordance with the present invention generallycomprise at least about 17%, for example, at least about 17.5% byweight, to about 55% by weight of binder polymer solids. Binders usefulin latex paint compositions are known in the art and include polymericbinders, such as acrylics, vinyl acrylics, or styrene acrylics binders.In one embodiment of the present invention, the paint composition isformulated to have a binder which is particularly compatible with thequaternary ammonium compound to avoid precipitation. The compatibilityof the binder with the quaternary ammonium compound is determined byobserving and measuring the degree of precipitation of binder andpigment when the quaternary ammonium compound is added to the paintcomposition as described in detail below:

Polymer/Quaternary Ammonium Compound Compatibility Test

Polymer preparation: Selected commercially available and proprietarypolymers were diluted to 23.5% weight solids in water.

Quaternary Ammonium compound preparation: Selected commerciallyavailable quaternary ammonium compounds were diluted to 50% of theiroriginal concentration in water to enhance accurate delivery.(BTC®2125M-80, BTC®1210, BTC®1010 and BTC®818 quaternary ammoniumcompounds from Stepan and Barquat® MB-50 and Bardac® 2250 quaternaryammonium compounds from Lonza.

20.0 g of diluted polymer was mixed by hand with sufficient dilutedquaternary ammonium compound to yield a concentration of 0.28% activequaternary ammonium compound in the 20.0 g polymer. The mixture wasstirred slowly for 5 minutes and allowed to sit at room temperature,covered, for 1 hour. Any liquid was poured off from the vessel. Theremaining solids were allowed to dry overnight at 70-77° F. thenweighed. A control for each polymer with no quaternary ammonium compoundwas prepared and the solids weight of the control was subtracted fromthe weight of the corresponding polymer/quaternary ammonium compoundsamples in order to account for any losses during handling. The weightof solids observed minus the weight of the control solids results in thecompatibility score. The binder polymers tested are listed in Table 1.The quaternary ammonium compounds tested are listed in Table 2. Theresults of compatibility testing for selected polymer/quaternaryammonium compound pairs is listed in Table 3. The term “compatibilityscore” for a polymer as used herein refers to the average compatibilityscore for that polymer with the six quaternary ammonium compounds testedand listed in Table 3.

TABLE 1 Zeta Monomer Stabilization Potential Diameter* Polymer ChemistryChemistry (mV) pH (nm) UCAR ™ Vinyl Nonionic −7.75 4.79 220 6045¹acrylic UCAR ™ Styrene Nonionic −7.08 9.03 98.5 461² acrylic ROVACE ™Vinyl Nonionic −2.6 4.33 328 661³ acetate/ butyl acrylate JONCRYL ®Acrylic Anionic/ −13.14 9.08 64 537⁴ Nonionic JONCRYL ® Acrylic Anionic/−24.77 8.14 135 1530⁵ Nonionic VINNAPAS ® Vinyl Anionic −20.66 4.15 214EF-811⁶ acrylic ACRONAL Acrylic Anionic −14.82 7.98 162 OPTIVE ® 130⁷Proprietary Vinyl Anionic/ −10.1 4.76 277 polymer A⁸ acrylic NonionicProprietary Acrylic Anionic/ −5.49 8.79 89.6 polymer B⁸ NonionicProprietary Latex Anionic −20.69 7.89 111.3 polymer C⁸ acrylic alkydProprietary Styrene- Anionic −13.71 8.55 93.1 polymer D⁸ acrylicProprietary Styrene- Anionic −21.75 8.36 89.9 polymer E⁸ acrylicProprietary Styrene- Anionic −7.75 4.79 220 polymer F⁸ acrylicProprietary Styrene- Anionic −17.26 7.98 87.4 polymer G⁸ acrylicProprietary Acrylic Anionic/ −22 7.96 153 polymer H⁸ nonionicProprietary Vinyl Nonionic −3.22 5.15 311 polymer I⁸ acrylic Combinationof Nonionic −4.3 5.15 UCAR ™6045/ Prop B (75/25) Combination of Anionic−18.64 8.46 Prop D and Prop E (50/50) *Intensity average diametermeasured by a Malvern Zetasizer Nano-S Dynamic Light ScatteringInstrument ¹Available from Arkema, Inc. ²Available from Arkema, Inc.³Available from Dow. ⁴Available from BASF. ⁵Available from BASF.⁶Available from Wacker Chemie. ⁷Available from BASF. ⁸Proprietarypolymers made by the assignee of the present application.

TABLE 2 Quaternary Ammouium Compound Trade Name Chemical Structure (%Active) BTC ® 2125 M n-Alkyl (60% C14, 30% C16, 5% C12, 5% C18) DimethylBenzyl Ammonium Chloride (40%) n-Alkyl (68% C12, 32% C14) DimethylEthylbenzyl Ammonium Chloride (40%) BTC ® 1210 Didecyl dimethyl ammoniumchloride (48.0%) Alkyl (50% C14, 40% C12, 10% C16) dimethyl benzylammonium chloride (32.0%) BARQUAT ® MB-50 Alkyl (C14 50%, C16 10%, C1240%) Dimethyl Benzyl Ammonium Chloride (50%) BTC ® 1010 Didecyl dimethylammonium chloride (80%) BARDAC ® 2250 Didecyl dimethyl ammonium chloride(50%) BTC ® 818 Octyl decyl dimethyl ammonium chloride (80%)

TABLE 3 BTC BTC BARQUAT BTC BARDAC BTC 2125M 1210 MB-50 1010 2250 818Score Score Score Score Score Score Aver- Standard Polymer (g) (g) (g)(g) (g) (g) age deviation PropI 0.06 0.02 0.07 0.04 0.01 0.01 0.04 0.03UCAR ™ 0 0.05 0.04 0.1 0 0.07 0.04 0.04 6045/Prop B (75/25) PropA 0.060.04 0.01 0 0.07 0.1 0.05 0.04 PropB 0 0.04 0.05 0.11 0.04 0.08 0.050.04 PropC 0.12 0.05 0.03 0.04 0.08 0.03 0.06 0.04 UCAR ™ 0.15 0.11 0.080.05 0.11 0.09 0.10 0.03 6045 Rovace ™ 0.14 0.12 0.19 0.15 0.09 0.050.12 0.05 661 PropF 0.04 0.06 0 0.41 0.14 0.08 0.13 0.17 Joneryl ® 0.020.23 0.08 0.27 0.04 0.19 0.14 0.11 537 UCAR ™ 0.09 0.16 0.07 0.16 0.190.21 0.15 0.06 461 PropD 0.11 0.38 0.03 0.4 0.4 0.37 0.28 0.17 PropE 00.27 0.08 0.51 0.64 0.31 0.30 0.24 D/E 0.15 0.52 0.13 0.03 0.53 0.6 0.330.25 (50/50) PropG 0 0.38 0.34 0.34 0.5 0.51 0.35 0.19 Joncryl ® 0.250.5 1 0.55 0.33 0.54 0.48 0.44 0.12 1530 Vinnapas ® 0.97 0.23 1.52 0.420.36 0.72 0.70 0.48 EF811 PropH 0.78 0.86 0.89 0.82 0.8 0.8 0.83 0.04Acronal 0.54 0.73 1.58 0.76 1.19 0.98 0.96 0.38 Optive ® 130

The compatibility score for each polymer is the average score for theabove test for all of the six quaternary ammonium compounds tested. Inone embodiment of the invention, the polymer has a compatibility scoreof 0.7 or less. In one particularly useful embodiment, the polymer usedin paint compositions in accordance with the present invention has acompatibility score of 0.5 or less. In a particularly preferredembodiment, the polymer used in paint compositions in accordance withthe present invention has a compatibility score of 0.35 or less. Itshould be noted that the average is used as the compatibility scorerather than the score for individual polymer/quaternary ammoniumcompound pairs. It has been determined that for polymers that have anaverage compatibility score of 0.7 or higher, even if a specificpolymer/quaternary ammonium compound pair had an individual score ofless than 0.7, that pair was not capable of making a stable compositionas defined herein. It has also been determined that for polymers havingan average score of 0.5 or less, that a pair having an individual scoreof above 0.5 were able to make a stable composition.

The prior art has typically taught away from using quaternary ammoniumcompounds in latex paints, because the combination results inprecipitation, i.e. a less stable composition. In one useful embodiment,the paint composition of the present invention is stable at roomtemperature for at least one week, for example, at least two weeks, andis also stable at 120° F. for at least one week, for example, at leasttwo weeks. As used herein, a “stable” composition has a change inviscosity of less than 15 Krebs Units (“KU”) measured by a StormerElectronic Viscometer Model KU1+(sample measured in a pint sized paintcan, filled ¾ full and adjusted to 77° F.±1° F.) after 1 week at 120° F.after the addition of a quaternary ammonium compound to the composition.In another useful embodiment of the invention, the paint composition hasa viscosity under 120 KU, for example from 85-120 KU, further forexample, about 90-110 KU as measured by a Stormer Electronic ViscometerModel KU1+.

The results of the stability test are unexpected and surprisingconsidering the zeta potential of the tested polymers. In general themagnitude of the zeta potential is an indicator of the stability of thepolymer. Polymer particles with a large (either negative or positive)zeta potential tend to repel each other and are less likely to cometogether and flocculate or precipitate out of the dispersion. Ingeneral, particles with zeta potentials more positive than +30 mV ormore negative than −30 mV are considered more stable. Indeed, particleswith zeta potentials of −5 mV to +5 mV generally see rapid flocculationwith particles having zeta potentials of ±5 mV to ±30 mV being onlyslightly more stable. In one embodiment of the present invention, usefulpolymers include those with zeta potentials between 0 mV and ±30 mV, forexample, polymers with zeta potentials between 0 mV and ±25 mV.

The paint composition of the present invention further comprises atleast about 10% by weight pigments. Such pigments may comprise inorganicpigments, such as titanium dioxide. The high quality paint compositioncomprises, for example, at least about 11% by weight, further forexample, at least about 12% by weight, further for example, at leastabout 13% by weight, further for example, at least about 14% by weight,further for example at least about 15% by weight, further for example,at least about 16%, further for example at least about 17%, further forexample, at least about 18%, further for example at least about 19%, andeven further for example at least about 20% up to about 30% by weighttitanium dioxide. In another useful embodiment, the high quality paintcomposition comprises more than 10% titanium dioxide. Other coloredpigments or dyes may also be added to the paint, alone or incombination, to produce a wide range of colored paint. Suitableadditional pigments may include calcium carbonate, talc, clay,silicates, aluminum silicates, calcium metasilicates, aluminum potassiumsilicates, magnesium silicates, barium sulfates, nepheline syenite,feldspar, zinc oxides or sulfides, or others known to those skilled inthe art. Such additional colored pigments may be included in amounts upto about 30% by weight, for example, about 10% to about 20%. In somecases, “pigments” may also refer to functional fillers which arenon-water soluble solids. Such functional fillers may include solidswhich provide additional functional characteristics to the paint, forexample, intumescent ingredients, such as ammonium polyphosphates,melamines, pentaerythritol and similar compounds. In one usefulembodiment, the coating composition of the present invention issubstantially free or totally free of intumscent ingredients such asammonium polyphosphates, melamines, and pentaerythritol and similarcompounds.

The pigment volume concentration, or PVC, of a coating is the ratio ofthe volume of pigments (including functional fillers) to the volume oftotal non-volatile material (i.e. pigment and binder) present in thecoating. The coating of the present invention preferably has a PVC ofabout 5 to about 60. In addition, the coating composition of the presentinvention has a maximum solids content of less than 65% by weight, forexample, about 25% by weight to about 60% by weight, further for exampleabout 30% by weight to about 58% by weight.

The composition may also include various other additives, including butnot limited to thickeners, such as urethane thickeners, and acrylicthickeners in amounts up to about 10% by weight, for example about 1% toabout 2%. Synthetic organic materials might also be incorporated; theseinclude plastic beads, hollow spheres or other similar materials. Otheroptional components include glycols such as ethylene and/or propyleneglycol in amounts up to about 7% and other solvents such as diethyleneglycol dibenzoate and dipropylene glycol dibenzoate in amounts up toabout 3%. The coating composition may also contain pigment dispersingagents which can be solvents or surfactants; wet paint preservatives;dry film preservatives; foam control agents such as oils, fatty acidsand silicones; slip and mar additives; adhesion promoters, and/or otherknown paint additives.

The paint composition of the present invention may also comprise otherbiocides including but not limited to metal ion containing compounds,polymeric biocides, heterocyclic compounds, phenols, organometallics,aldehydes, proteins, peroxygens, alcohols, enzymes, polypeptides, andhalogen releasing compounds.

Paints made in accordance with the present invention are generallyformulated to have a pH between 7 and 10.

It has been observed that by premixing the quaternary ammonium compoundswith a mixture of ester alcohols and oleic acid monoester propyleneglycols that higher concentrations of quaternary ammonium salts can beachieved. This method comprises mixing together quaternary ammoniumcompound, with an ester alcohol, such as Texanol™ solvent, and oleicacid monoester propylene glycol, such as Loxanol® EFC, and then addingthe mixture to the paint composition. In one embodiment, the esteralcohol and oleic acid monoester propylene glycol are functionalcomponents of the paint composition. In one useful embodiment the esteralcohol and oleic acid monoester propylene glycol are added to the paintcomposition only by this method. In another embodiment, portions of thenormally used amounts of the ester alcohol and oleic acid monoesterpropylene glycol are used to prepare the premix. For example, in oneembodiment, about half of the normally used amounts of the ester alcoholand oleic acid monoester propylene glycol may be mixed with thequaternary ammonium compound for addition to the paint composition.

In another embodiment, the quaternary ammonium compound included in thepaint composition may be encapsulated within a solid shell(“microcapsule”) material. Microencapsulation of the quaternary ammoniumcompound serves to protect the paint from flocculation by minimizing oreliminating direct interactions between the quaternary ammoniumcompounds and the latex binder and other paint ingredients. In oneembodiment, the microcapsule completely isolates the quaternary ammoniumcompound from interaction with the other paint components. Themicrocapsule may have a structure which allows it to isolate thequaternary ammonium compound from the rest of the paint components, butopens or bursts upon drying of the paint film to allow the quaternaryammonium compound to contact and kill or inactivate microorganisms orviruses which come into contact with the dried paint film surface. Forexample, the capsule could be designed to open as the pH of the systemchanges as the paint dries. In another embodiment, the evaporation ofwater from the system could cause the capsule to desiccate and burst.Means for encapsulating active materials (also referred to as deliverysystems) are known to those of ordinary skill in the art. Any suchmethods which are known or are later developed may be used in thisinvention.

It should be noted that in order to make a latex paint formulation, anappropriate dispersant/surfactant system is needed in order to dispersethe pigments in the paint formulation. The process for selectingdispersants/surfactants for paint formulations is well known to those ofordinary skill in the paint formulation art. After selecting acompatible polymer and quaternary ammonium compound as described herein,one of ordinary skill in the art would be able to select adispersant/surfactant combination in order to make a desired paintcomposition.

In one useful embodiment, the dried paint film is capable of reducinggram positive bacteria, gram negative bacteria, and viruses by greaterthan 3 logs within 2 hours of application. The bacterial and viralreduction is measured in a test based on the JIS Z 2801 modified forpaints as described herein and compared to a control paint that does notcontain a quaternary ammonium compound.

EXAMPLES

Exemplary stable, high quality paint formulations were made by mixingthe following components using techniques known to those of ordinaryskill in the art:

Comparative Example

COMPONENT Weight % UCAR ™ 6045 30.62 Proprietary Polymer B (55% solids)8.19 Defoamer¹ 0.25 WATER 19.73 Hydroxyethyl cellulose thickener² 0.02Dispersant³ 0.49 Titanium Dioxide (dry) 23.29 Pigment⁴ 9.05 Pigment⁵3.45 Coalescent⁶ 0.26 Rheology modifier⁷ 2.85 Rheology modifier⁸ 1.29Nonionic surfactant⁹ 0.43 Aqueous ammonia 0.08 Total 100 ¹BYK ® 024 fromByk Chemie ²CELLOSIZE ™ QP-4400H from Dow ³TAMOL ™ 1254 from Dow.⁴MINEX ™ 4 from Unimin Specialty Minerals ⁵MINEX ™ 2 from UniminSpecialty Minerals ⁶LOXANOL ™ EFC 100 from Cognis ⁷ACRYSOL ™ RM-8W fromDow ⁸ACRYSOL ™ RM-2020 NPR from Dow ⁹TRITON ™ X-102 from Dow

Example 1 was made by adding 0.65 g of Barquat MB-80 Quaternary AmmoniumCompound to a paint prepared in accordance with the Comparative Examplethen stirring with an air mixer at room temperature for 10 minutes.

Paint compositions as described herein were tested for antimicrobialactivity. Paint coupons for the bacterial testing were made using thefollowing procedure: A 7 mil wet film caster was used to draw downHARMONY® interior acrylic latex (flat, extra white) paint on a blackLeneta scrub chart P121-10N. The base coat was air dried overnight and a7 mil film caster was then used to draw down the paint of Example 1 overit. After air drying overnight, a second 7 mil coating of Example 1 wasapplied and allowed to air dry overnight. A control with a base coat ofHarmony® interior acrylic latex paint and two coats of the ComparativeExample paint was made using the same process. An additional controlsample consisting of unpainted Leneta chart was tested in the samemanner as the paint samples.

To test the paint's ability to kill bacteria, Japanese IndustrialStandard JIS Z 2801 was used with the following adaptations: The E. coliATCC 11229 was used instead of ATCC8739 and 0.3 ml organic soil load (25mL Fetal Bovine Serum+5 mL Triton X-100) was added to the culture. Three1 in×1 in pieces of Parafilm laboratory film were placed in a sterileglass Petri dish and a 20 cm×20 cm sample from the center of the paintdrawdown was placed on each of the prepared coupons. Twenty-five pi ofinoculum were placed on the paint surface. After inoculation, thesamples were covered with a glass coverslip and incubated for 2 hours atsaturation humidity. The comparative example paint was processed in thesame way as the paint of Example 1. The bacteria was recovered byplacing the paint square, parafilm and coverslip in a sterile 50 mlconical tube filled with 5 ml of phosphate buffered saline (PBS) andvortexed for 15-30 seconds to release the remaining bacteria back intosolution. A total viable count (TVC) was performed on the eluentsolution. Colony Forming Units/milliliter (CFU/ml) of bacteria recoveredfrom each sample was calculated, and results were reported as the logreduction in CFU/ml of the antimicrobial paint compared to the untreatedpaint. A measurement of the CFU/ml of the inoculum was made bytransferring 25 μl bacterial culture directly into a sterile 50 ml tubecontaining 5 ml of PBS, and completing the test method. The CFU/ml ofthe Staph innoculum was determined to be 9.7×10⁵ and the CFU/ml of theE. Coli innoculum was determined to be 1.0×10⁶. The effectiveness of thetest conditions was judged to be adequate because the CFU/ml of theinnoculum was between 2.5×10⁵ and 1×10⁷ CFU/ml and the CFU/ml of theunpainted Leneta chart and parafilm control and the comparative examplewere between 5 and 6.7 Log₁₀ CFU/ml.

The results of the antimicrobial testing for these paints are summarizedin Table 4.

TABLE 4 Log₁₀ CFU/ml, Log₁₀ CFU/ml, Sample S. aureus 2 hrs E. coli 2 hrsUnpainted Control 5.6 5.9 Comparative example: 5.5 5.3 Example 1: 1.21.3 Log reduction 4.4 4.6

Separate paint coupons for viral testing were made using the sameprocedure as described above for the bacterial testing except that nounpainted films were used. To test the paint's ability to inactivateviruses, the following procedure was used. A Stock Influenza A virus(ATCC VR-544 Strain Hong Kong) in Minimum Essential Medium, containing1% fetal bovine serum was used in this test. The stock virus was storedat ≤−70° C. On the day of testing, the stock virus was titred by 10-foldserial dilutions and assayed for infectivity to determine the startingtiter of the virus. The starting titer for the test was 1×10^(7.75)TCID_(50%)/0.10 ml.

Replicate 1 in×1 in coupons coated with the paints of the ComparativeExample and Example 1 were placed in sterile Petri dishes. The couponswere irradiated with UV light for about 15 minutes on each side. Thesamples were inoculated with a 100 μl aliquot of the test virus. Theinoculum was covered with carrier film (20 mm×20 mm prepared from asterile stomacher bag) and the carrier film was pressed down so that thetest virus spread over the film but did not spill over the edge of thefilm. The exposure time began when each sample was inoculated. Thesamples were transferred to a controlled chamber set at 20° C. in arelative humidity of 40% for the duration of the exposure times. Thecoupons were kept in contact with the virus for 1 or 2 hours at 20° C.and 40% relative humidity.

Following each exposure time, a 1.00 ml aliquot of test medium (MinimumEssential Medium supplemented with 1% v/v heat inactivated fetal bovineserum, 10 micrograms/ml gentamycin, 10 units/ml penicillin, and 2.5micrograms/ml amphtericin B) was individually pipetted onto each testand control paint coupons as well as to the underside of the film usedto cover each sample. The surface of each paint coupon was scraped witha sterile plastic cell scraper. The test medium was collected, mixedusing a vortex type mixer and serial 10-fold dilutions were prepared.The serial dilutions were assayed for infectivity on Rhesus monkeykidney cells. The geometric mean of two TCID_(50%) (Tissue CultureInfective Dose)/0.1 ml replicates for each of the Comparative exampleand Example 1 was determined and the log reductions at each contact timewere calculated by subtracting the result of Example 1 from theComparative Example.

The results of the viral testing for paints made in accordance with thepresent invention are summarized in Table 5

TABLE 5 Mean TCID_(50%)/0.1 ml Mean TCID_(50%)/0.1 ml (Tissue Culture(Tissue Culture Infective Dose) Infective Dose) Sample at 1 hour at 2hours Comparative control:  7.63 Log₁₀  7.38 Log₁₀ Inventive example:≤1.5 Log₁₀ ≤1.5 Log₁₀ Log reduction ≥6.13 ≥5.88

The invention claimed is:
 1. A latex paint composition comprising: (a) abinder copolymer comprising an acrylic component and a second polymericcomponent comprising one or more of a vinyl component and styrenecomponent and having a compatibility score of 0.5 or less; (b) fromabout 0.25% by weight to about 3.0% by weight of a quaternary ammoniumcompound; (c) a hiding pigment; and (d) water, wherein the paintcomposition has a pigment volume concentration (PVC) of about 5 to about60; wherein the quaternary ammonium compound is present in a suitableamount to provide one or more of (1) gram negative bacterial reductionby greater than 3 logs within 2 hours of application of the gramnegative bacteria to a dried surface of the paint composition; (2) grampositive bacterial reduction by greater than 3 logs within 2 hours ofapplication of the gram positive bacteria to a dried surface of thepaint composition; or (3) viral reduction by greater than 3 logs within2 hours of application of the virus to a dried surface of the paintcomposition, wherein the paint composition has a dried paint film glossof 5 to 85 gloss units measured at 60°.
 2. The latex paint compositionof claim 1, wherein the hiding pigment comprises one or more of calciumcarbonate, talc, clay, silicates, aluminum silicates, calciummetasilicates, aluminum potassium silicates, magnesium silicates, bariumsulfates, nepheline syenite, feldspar, zinc oxides, sulfides, titaniumdioxide, or mixtures thereof.
 3. The latex paint composition of claim 1further comprising at least one additional pigment other than titaniumdioxide in an amount up to about 30% by weight.
 4. The latex paintcomposition of claim 1, wherein the paint composition is substantiallyfree of an intumescent ingredient.
 5. The latex paint composition ofclaim 1, wherein the paint composition has about 30% to about 60% byweight solids.
 6. The latex paint composition of claim 1 furthercomprising a biocide, said biocide comprising at least one of a metalion containing compounds, a polymeric biocides, a heterocycliccompounds, a phenols, an organometallics, an aldehydes, a proteins, aperoxygen, an alcohols, an enzymes, a polypeptides, or a halogenreleasing compounds.
 7. The latex paint composition of claim 1, whereinthe quaternary ammonium compound is substantially free of silicon. 8.The latex paint composition of claim 1, wherein the quaternary ammoniumcompound has the structural formula:

wherein R₁ and R₂ are linear or branched chain alkyl groups or mixturesof groups having 1-7 carbons, R₃ is a linear or branched chain alkylgroup or a mixture of groups containing 6-20 carbons, and R₄ is a linearor branched chain alkyl group or a mixture of groups having 6-20carbons, benzyl or alkyl benzyl groups, or

where R₃ and R₄ may be the same or different from each other, and Xrepresents a halide, carbonate, methosulfate, or saccharinate.
 9. Thelatex paint composition of claim 1, wherein the quaternary ammoniumcompound has the structural formula:

where R₁ is C₈-C₁₈-alkenyl or -alkenyl, where R² is C₈-C₁₈-alkyl or-alkenyl, aryl or C₇-C₁₈-aralkyl, in which the aromatic rings canadditionally be substituted, where R₃ is C₁-C₄-alkyl, where R₄ is H ormethyl, and where A is an anion of an organic or inorganic acid.
 10. Thelatex paint composition of claim 1, wherein the quaternary ammoniumcompound comprises one or more of n-alkyl dimethyl benzyl ammoniumchlorides, the n-alkyl being a C₈-C₁₈ alkyl, benzalkonium chloride, thealkyl side chain being C₈, C₁₀, C₁₂, C₁₄, C₁₆ or C₁₈ or mixturesthereof, n-alkyl dimethyl ethylbenzyl ammonium chlorides, the n-alkylbeing a C₈-C₁₈ alkyl, dialkyl dimethyl ammonium chlorides, the alkylside chain being C₆-C₁₂, n-alkyl dimethyl benzyl ammonium chloride, anddodecyl dimethyl ammonium chloride, octyl decyl dimethyl ammoniumchloride, dioctyl dimethyl ammonium chloride, didecyl dimethyl ammoniumchloride, or mixtures thereof.
 11. The latex paint composition of claim1, wherein the quaternary ammonium compound is in a microcapsule. 12.The latex paint composition of claim 1, wherein the binder polymer ispresent at about 7% to about 30% by weight.
 13. The latex paintcomposition of claim 1, wherein the pigment has a minimum fineness ofgrind by Hegman gauge of at least
 4. 14. The latex paint composition ofclaim 1, wherein the pigment has a minimum fineness of grind by Hegmangauge of at least
 5. 15. The latex paint composition of claim 1, thepaint composition further comprising a pigment dispersing agent.
 16. Thelatex paint composition of claim 15, wherein the pigment dispersingagent comprises one or more of a solvent or surfactant.
 17. The latexpaint composition of claim 15, wherein the pigment dispersing agent ispresent at lower than about 0.5% by weight.
 18. The latex paintcomposition of claim 1, wherein the quaternary ammonium compound ispresent in a suitable amount to provide reduction of E. Coli ATCC 11229by greater than 3 logs within 2 hours of application of the bacteria toa dried surface of the paint composition, wherein the quaternaryammonium compound-comprises one or more of n-alkyl dimethyl benzylammonium chlorides, the n-alkyl being a C₈-C₁₈ alkyl, benzalkoniumchloride, the alkyl side chain-being C₈, C₁₀, C₁₂, C₁₄, C₁₆ or C₁₈ ormixtures thereof, n-alkyl dimethyl ethylbenzyl ammonium chlorides, then-alkyl being a C₈-C₁₈ alkyl, dialkyl dimethyl ammonium chlorides, thealkyl side chain being C₆-C₁₂, n-alkyl dimethyl benzyl ammoniumchloride, and dodecyl dimethyl ammonium chloride, octyl decyl dimethylammonium chloride, dioctyl dimethyl ammonium chloride, didecyl dimethylammonium chloride, or mixtures thereof.
 19. The latex paint compositionof claim 1 having a viscosity of under 120 KU.